Many door panels in use today utilize fiberglass reinforced plastics to form part or all of the door panels. Fiberglass reinforced plastics are also referred to as FRP, as fiberglass, as glass reinforced plastics, as GRP, and as reinforced polymer composites. All of these various terms are synonymous and, for the purposes of this application, refer to the same material system and will be used interchangeably. Ordinarily, doors constructed of fiberglass reinforced plastics have a pair of spaced stiles that form the door edges, a top and a bottom rail, and a pair of skin members that form the door faces. Such doors are commonly referred to as being of composite construction. A core material such as foamed plastic often is used to fill the interior void space so as to increase the rigidity of the door and to provide insulation. The hinge side stile must be of sufficient width and strength to receive and support the door mounting hinges. Likewise, the lock, or strike side stile must be able to receive and support a door latching and locking mechanism that extends out from the edge of the door to engage a recess in the door frame.
There are currently no trade-accepted descriptions or definitions of the features that make up a "fiberglass door." Several different types of door panels are commonly described in the market place as being that. Included within those common marketplace descriptions are first, door panels that have a sub-structure made from a structural material such as steel, wood, or aluminum, and have bonded to that sub-structure a pair of face sheets or panels constructed of fiber reinforced resin. Another type of door panel that is commonly called a fiberglass door is one that has an all fiberglass internal and external composition, but that also relies on one or more non-fiberglass internal structural members to provide for a required performance trait.
A specific example of a composite door of the first type found in the patent literature is U.S. Pat. No. 5,239,799 to Bies et al. This patent describes a door having a pair of stiles that form the side edges of the door, a top rail extending between the stiles, and a pair of door facing skins that are molded from fiber reinforced resin. The skins are adhesively bonded to the stiles and the top rail, and have edge flanges which abut to form the top and bottom edges of the doors. A foamed plastic such as polyurethane is injected into the interior void space formed between the stiles, the top rail and the bottom flanges. A door construction generally similar to that described in the Bies et al patent is disclosed in U.S. Pat. No. 5,074,087. It shows a door of composite construction, having an internal door frame formed of a pair of stiles and top and bottom rails, with a pair of molded fiberglass skins bonded to the frame. Another example is that of the Thorn patent, U.S. Pat. No. 4,922,674. That patent shows a door that does not use either side stiles or top and bottom rails. Rather, the door is constructed of a pair of molded fiberglass panels that fit together to form a sandwich. Reinforcing mounting blocks are provided at the hinge and lock locations, and a preformed core of foamed plastic or other insulating material is inserted into the cavity formed between the panels.
Yet another type of door panel commonly referred to as a fiberglass door has an all fiberglass internal and external composition, with no other material systems used to provide structural support. That mode of construction is illustrated by U.S. Pat. No. 4,068,431, issued to William Pitt. The Pitt patent describes a door which uses a single-piece, stile and rail frame or collar constructed of fiberglass reinforced resin. Both style and rail portions of the collar display an inwardly opening, U-shaped configuration with the base, or bight, portion of the collar forming the door edge.
When a door panel is manufactured, the dimensions of the door panel are set by its maker to fit a frame opening of a specific size. The dimensions of the frame opening, in turn, ordinarily conform to the standards set by the door industry. A door panel, fabricated to fit a specific frame opening, will function with complete satisfaction provided that the dimensions of the frame remain constant, that the dimensions and geometry of the door panel remain constant, and that the alignment of the frame remains true. Problems arise in installing door panels within their frames when either the dimensions or the alignment of the frame go out of specification.
Out of specification conditions can arise from a number of different causes. For example, a building might shift or settle, and the wall in which the frame is set forces the frame out of square and alignment. In a masonry building, if the opening set by the mason is not square and plumb and if the frame installer uses the wall as a template, the frame opening will not fit the door panel. Over a period of time, a door frame may be subjected to torquing from traffic abuse sufficient to cause the frame opening to come out of square and plumb. Metal frames may corrode over time to the point where lower extremities of the jamb are pushed out of alignment, and the opening becomes narrower at the bottom than at the top. The installed door then binds on various parts of the frame.
There are many instances where it is not practical, or even possible, to modify a door frame that is out of dimensional specification. In those instances, it is the door panel that must be altered to make it fit the frame opening. Modification of the door panel requires that a stile or rail of the door be cut or shaped to conform with the frame opening. A wood door typically is constructed with rather wide stiles and rails that can be cut or shaped to fit the a particular frame opening without structurally weakening the door panel, and without undue change to its appearance. A steel door presents a more complex situation, but a skilled installer can cut an edge, side or top, and weld back a modified edge plate. Some patio and storm doors are provided with an adjustable sleeve on one or both of the stiles that can arranged to provide an acceptable fit with the frame. A variety of accessories are also offered by a number of different manufacturers to cover, extend, patch and modify the stiles of steel doors. In most instances, however, it is very obvious that the panel has been modified.
To this time, the fabricators of doors constructed entirely of fiber reinforced plastic, or fiberglass, have offered only door panels that have fixed and unalterable stiles. One important reason for that circumstance is that a feature offered by most manufacturers is that the door as shipped by the factory has an interior cavity that is completely sealed off from exterior contamination. The fact that the structural integrity of the door is largely dependent upon a seamless bond between the structural frame components of the door and the face sheets allows, almost by default, for that feature to be offered at no additional expense to the buyer. Because the stiles of a fiberglass door are essential to the structural soundness of the panel, any field alteration of the door's dimensions can result in breaking of the seal to the interior cavity and weakening of the door. In most instances, any field alteration of the door will void the manufacturer's performance warranty as well. Further, it is not technically feasible or cost effective to provide a wide, solid stile, as in a wood door, to allow for the door to be field altered.